1. Field of the Invention
Embodiments of the present invention generally relate to apparatus and methods for substrate processing using microwave radiation.
2. Description of the Related Art
To match the constant demand for smaller and more powerful devices, the size of integrated components on semiconductors is decreasing. As features on semiconductor devices become smaller, advanced polymers and dielectrics have been developed to allow features to become more compact. These new dielectrics and polymers employ increased porosity to provide characteristics consistent with decreasing size and increasing compactness.
Deposition of high-quality metal films requires clean surfaces free of residues and desorption of volatile materials. It is common practice in semiconductor fabrication and packaging to use a thermal degas process often followed by a cleaning prior to metal deposition. These processes are typically carried out in-situ (without air exposure prior to metal deposition) to avoid recontamination of the substrate and incoming films. The thermal degas process typically involves heating the substrate on a hot plate, in a convection oven or using infrared heating by a lamp array.
Degassing has previously been done by heating of the substrate, with either a heating plate or infrared (IR) radiation lamps. However, both of these thermal heating embodiments are not sufficient in degassing modern films. Thermal heating takes quite a long time and results in very low productivity of the tools. Further, standard thermal processing can easily bring modern films to a temperature which produces oxygen-containing secondary gases or leads to glass transition of the layer.
Thus, there is a need in the art for methods and apparatus which allow for efficient degassing of the film while maintaining heat with the thermal processing ranges of the deposited film.